Around the time Radiohead took the stage on Wednesday evening at Madison Square Garden, concerned citizens elsewhere in the city were huddled before televisions, awaiting encouraging words from Vice President Joseph Biden. The backdrop of troubled times, with Americans of all persuasions feeling their nation is in danger, suited a band whose lyrics traffic in vague but pervasive dread. But for the crowd here, who had waited over four years since the band's last tour, the mood was more jubilant than fearful.

Sure, the band announced its entrance with audio clips of speakers offering to "tell you what freedom is," as if it were something so foreign it needed explaining; sure, they blanketed the stage in blood red lights while opening with new song "Burn the Witch," in which frontman Thom Yorke exhorts listeners to "stay in the shadows ... we know where you live." But that hardly cowed fans, who waited giddily for the new material to give way to old favorites, one or two of which would be rare treats.

"Witch" was delivered here without the string arrangement it wears on the new record A Moon Shaped Pool, Jonny Greenwood's bowed guitar being the only nod to the original. If anything, this tour goes in the opposite direction of an album that enlists the London Contemporary Orchestra and choral vocals: The only addition to the five-piece band here was a second drummer, who came out from time to time to double-down on percussive energy. Greenwood sometimes set his guitar aside to drum as well, beating something like a street samba on "Bloom," from 2011's The King of Limbs. And for "There There," a crowd-pleaser from Hail to the Thief, guitarist Ed O'Brien did the same, with four men drumming to end the main set.

This tour's light show placed six vertical screens above the band, which often featured the players in artful, monochrome close-ups — making them as fragmented visually as they were united in their distinctive thick sonic wash. At other points, the screens' live-mixed performance footage gave way to bristling abstractions, none more aggressive than the hypnotically intense pale green and pink assault accompanying "Planet Telex," whose wall of bracing guitars recalled My Bloody Valentine.

Multiple layers of scrims behind the band sometimes were lighted to suggest an infinitely receding background that might swallow them up; elsewhere they turned opaque as deep blues or purples made the players disappear before us. But the lighting design was deliberate in its resets, sometimes cutting to plain white, "show's over" illumination as crew members shuffled guitars and keyboards on and off stage. "It's like we're playin' a game of tennis," Yorke observed of the back-and-forth action between numbers.

That was nearly all the singer said (not counting a few "thank you"s) until the first encore, when, without singling out any specific event, he worried aloud about the "crazy broken shit going on" in the world. "We really, really need to wake up," he continued, to much applause.

Those in the crowd who didn't register any political urgency in that message — it is, after all, possible to spend a couple of hours listening to Yorke's wandering falsetto while missing his lyrics' gloom — woke up in a different sense a couple of songs later, when (reportedly for the first time in a dozen years) the group played "Creep" for an American audience. Blinding white lights turned on the crowd, catching thousands of fans waving hands in the air and singing "I don't belong here" before filing out of the Garden, back into the frightening world.